Heretofore, attention has been paid to a semiconductor device (semiconductor power device) for use chiefly in a system in various power electronics fields, such as a motor control system or a power conversion system.
For example, FIG. 1 of Patent Literature 1 discloses a Schottky barrier diode in which SiC is employed. This Schottky barrier diode is composed of an n type 4H—SiC bulk substrate, an n type epitaxial layer that has grown on the bulk substrate, an oxide film that is formed on a surface of the epitaxial layer and that partially exposes the surface of the epitaxial layer, and a Schottky electrode that is formed in an opening of the oxide film and that makes a Schottky junction with the epitaxial layer.
FIG. 8 of Patent Literature 1 discloses a vertical MIS field-effect transistor in which SiC is employed. This vertical MIS field-effect transistor is composed of an n type 4H—SiC bulk substrate, an n type epitaxial layer that has grown on the bulk substrate, an n type impurity region (source region) that is formed on a surface layer part of the epitaxial layer, a p type well region that is formed adjacently to both sides of the n type impurity region, a gate oxide film that is formed on a surface of the epitaxial layer, and a gate electrode that faces the p type well region through the gate oxide film.